Repairing and testing means for contactless thermal protectors.



P.B.GO0K. REPAIRING AND TESTING MEANS FOR GONTAOTLBSS THERMALPROTECTORS.

APPLIUATION FILED JULY28.1905.

906,61 5. Patented Dec. 15, 1908 FRANK B. COOK, OF CHICAGO, ILLINOIS.

REPAIRING AND TESTING MEANS FOR CONTACTLESB THERMAL PROTECTORS.

No. 9oe,e15.

Specification of Letters Patent.

Patented Dec. 15, 1908.

Application and m 28, 1905. Burial 110. 271,662.

To all whom it may concern:

Be it known that I, FRANK B. Coon, a citizen of the United States ofAmerica, and a resident of the city of Chicago, in the State ofIllinois, have invented new and useful Repairing and Testing Means forC011- tactless Thermal Protectors, of which the following is aspecification, reference being had to the accompanying sheet ofdrawings, illustrating same.

The electrothermal protector herein illustrated is an improvement on myUnited States Letters Patent No. 785,797, issued March 28, 1905, forthermal cut-out for electrical circuits.

My invention relates to thermal protectors such as are used forrotecting electrical circuits and apparatus rom abnormal electriccurrents.

My object is, first, to provide a protector in which there are no loosecontacts in the circuit, that is, a protector in which all of thecontacts, either in the protector or between the latter and its mountingand o erating members, are normally soldere and second, to provide meanswhereby this protector may be automatically repaired after operation,for another operation.

Heretofore, it has been the practice to provide a heat coil or thermalprotector which is removably mounted in the circuit which it is toprotect, so that the contacts with the protector are merely pressurecontacts. With this form of protector, corrosion of the pressurecontacts, or dust, dirt or the like, therein, may produce an opencircuit or give a contact of very high resistance.

In this present invention it is my intention to provide a protector inwhich there are no pressure contacts, and thus do away with theob'ectionable features of the latter. Consequently I provide a protectorin which all of the contacts, in the, protector or between the latterand its cooperating members, are soldered. When the protector operates,certain soldered arts separate and thus open the circuit t rough thedevice. To reset the device to o erative position, I provide mechanism wich automatically presses the separated parts back together,

eats the solder, and resolders the parts in their normal positions.

I will more particularly describe my invention by reference to theaccompanying drawings, in which,-

Figure 1 is an elevation of the protector and repairing device, showingthe preferred construction thereof, with portions shown incross-section; Fig. 2 is a plan view of Fig. 1; Fig. 3 is an enlargedview of the protector of Fig. l, with portions shown in cross-section;Fig. 4 is an end view of the heating element of Fig. 3; and Fig. 5 showsa modified form of thermal protector.

Like characters refer to like parts in the several figures.

B is preferably a piece of graphite or carbon, plated with metal at itsends over the portions 0 and n and turned away at m to adjust theresistance thereof to any desirable value. In making this element B thewhole piece of resistance material may be electroplated all over, withcopper or any suitable metal, and the portion m turned down to removethe portion of the platin at m and adjust the resistance of B to t edesired value. The plated end portions 0 and n of e B are then solderedto the metallic members 9 and l by heat-susceptible material [9,preferably a low-melting-point metallic solder. The solder p, at 11,may, if desired, be a hard solder, as this joint in this construction ofmy invention is not required to open when the device operates.

An abnormally large current of electricity passing through the element Bfor a short length of time, heats the same and thereby softens thesolder p and allows the spring member 9 to separate from the element Band take the position 3 of Fig. 1, preferably against the ground p ate7. This operation of the protector o ens the circuit through same andpreferably switches the objectionable current to earth. The portion n ofB is preferably enlarged to provide a. suitable bearing surface to restagainst memher 1. Spring 9 is preferably formed into a thimble at g, toprovide a. suitable surface to be soldered to the end portion a of B.

When spring q separates from the element B, the solder p, at o, isdisarranged so that after it cools, the thimble g, cannot be fullyreplaced upon the end portion 0 until the solder p is resoftened.

When the thimble g, is soldered to the end portion 0 of B, it is simplysprung in place, which uts it under tension for operatin the device, andis held there until the solder cools. This soldering may be accomplishedby a soldering iron, by an automatic means, or in any desired manner. Asspring 9 and member Z are rigidly mounted to a suitable support, springg is pressed to its operative position where it is soldered to 0,without in any way putting the device or apparatus un der binding orbuckling stresses which are found in other forms of protectors when theapparatus is set, and which greatly reduce the etliciency of theoperation of such devices. It will be readily seen in my presentinvention, that when spring g operates it. moves in exactly the oppositedirection from which it was moved to set the llt\'l(l. and hence thereis no lllltllllg ol' the part when tliedevice operates, and the latteris not under unnecessary stresses while set.

in Fit!- 5 l have -ho \'n a lllOtllliE'tl form ol protector in \vhil-htln' heatprodm'ing wind ing 111 takes the plauot the rnrhor. or graphiterod l5. A metallic plate n, is Ul' dered to the support l. by solder pand is rigidly secured to spool m, but Insulated therefrom by aninsulating disk 21,. inding m is connected in circuit with spool m, andplate 11 An insulating shell in, incloses the winding 'm,. The operationot the device is similar to that of the (,iLYli'e of Fig. 3. Theinsulating disk in being placed between spool m and plate n confines thegreater part of the heat to the end 0 of spool m and hence this endunsolders when the device operates. and the other end does not. Thenagain the heavy part l. conducts and radiates more heat from its solderjoint 7; than spring does from the solder joint at 0, with the samedegree of heating, and this fact also tends to keep the joint between n,and I, from opening when the device operates. In the automatic repairingmeans A, the insulating handleportion a carries a light flexible spring0 and a stiff conducting member b. A lever j is pivoted at g on a blockof insulating material h which is mounted on the member I). A coilspring i is secured to lever f and member b. being insulated from thelatter by an insulating bushing j. Spring 1' tends to pull lever f fromthe position f to f,. A thumbpiece 8 is provided for pressing the leverfrom the position to the position A source of electricity 1/ and anindicating device. or the like, are connected in circuit with spring rand member I). The circuit of battery 11' through the tool is normallyopen between spring (2 and lever f, as the latter is normally in theposition f, and consequently out of contact "with spring 0 which isnormally in the position 0,.

To repair the heat coil and reset same to operative position afteroperation. the end of member 0 is first placed against an offset k inmember I. Then by pressing on the thumb'piece a of lever the latter ispressed from the position f, to the position f. against the tension inpring i which is now stretched. Then the end of lever f is hooked g, andthe thumb-piece 8 released. Now the thimble q, is moved by the leverffrom the position q, of Fig. l, to against the solder at 0. which closesthe circuit. of battery 11' through the resistance member m. in a feweconds the current from battery (I heats the resistance m and softenssolder p which allows thiinble to slip clear upon portion 0, due to thepressure of lever f, and the latter to take the position f,. The circuitof bat (cry (I is now broken between spring 1: and lt\ or f andtherefore the solder 1 tools and rsnltlt'lfi thiinble q, to portion 0 asoriginally. When the solder has cooled sufficiently, the device may beremoved. The protector is now in position and condition to be operatedagain as originally. The cycle of operations, comprising the operationand repairing ot' the protector may be repeated as many times asdesired. It will be seen that the repairing and resetting of theprotector also tests the serviceable condition of same, as it cannot bereset and resoldered unless it is in proper condition to operate again.

With the repairing device herein shown, the a)paratus cannot be strainedin resetting, efore the solder is sufiiciently sof tened to againresolder the parts together, as the resetting is done by spring 1' andthe tension of this spring is suitably adjusted to prevent suchstraining. Neither can the protector be overheated in resetting, as thecurrent from battery 4 is automatically cut oil as soon as the device isfully reset. The in dicating instrument 6 may indicate when the device18 fully reset.

When it is desired to test the line, the solder joint at 0 may beunsoldered b the aid of the device A by engagin mem er b with su port Iand lever f wit the inner side of die end of spring and then depressingthe thumb piece 8 sh iitly. This connection closes the circuit 0%battery (1 through the heating element m (or m heats the lat tor andunsolders spring g which springs to the position q. This nnsoldering ofspring (1 may also be accomplished with an ordinary soldering iron.

I do not wish to limit this invention to the particular arrangement ordetaih of run sil'llt'llUll herein shown. The principles in volved arewhat I more particularly desire to claim.

Having thus described my invention, what, I claim as new and desire tosecure by Let ters Patent, is

l. A repairing device for an electrothermal protector having a solderedjoint openable upon excessive heating, comprising means for closing thesaid joint and thereby applying current through the protector to heatthe said joint. and switching mechau ism adapted to autonnitit'ally openthe cir- 1 rllit through the protector when same is saf over the freeend of spring I in the position ticiently heated.

2. A repairing device for an electrothermal protector, comprising meansfor closing a joint in the protector and thereby applying currentthrough the protector to heat same, and switching mechanism adapted toautomatically open the circuit through the protector when same issutliciently heated for purposes substantially as described.

3. A repairing device for an electrothermal protector having athermally-openable joint, comprisin electromechanical mechanism adaptedto e applied to the protector after operation to close the said jointand thereby cause current to flow through the protector to heat same,and switching mechanism for automatically stopping the flow of currentthrough the protector when same is sufficiently heated, to allow theprotector to cool whereby the said joint is resecured preparatory toanother operation.

4. A repairing device for an electrothermal protector having an openablejoint normally held against opening by heat-susceptible material,comprising means for closing the said joint and thereby sending currentthrough the protector to soften the heatsus ceptible material, andswitching mechanism for automatically stopping the flow of currentthrough the protctor when same has been sutliciently heated, the saidmeans being adapted to hold the arts of the protector in reset positionwhile the heat-susceptible material cools and thereby secures the jointin closed position.

5. A repairing tool for electrothermal protectors comprising ahandle-portion, a metallic contact strip, an insulating support, a leverpivoted on the insulating support and provided with a thumb-piece to bedepressed, a s ring member controlling the said lever, an a secondspring member adapted to make contact with the said lever when thethumb-piece is depressed; and a source of electricity in circuit withthe said metallic contact strip and second spring member.

6. A repairing device for an electrothermal protector havingheat-producing means and an openable joint normally held closed byheat-susceptible material, comprising a suitable handle portion, ametallic contact strip, an insulating support, a lever pivoted on theinsulating support, a coil spring controlling the said lever, and acontact sprin arranged to make contact with the said lever when the coilspring is placed under tension; and a source of electricity and anelectrical indicating instrument connected in circuit with the saidmetallic contact strip and contact spring, the said device being adaptedto be applied to the protector to automatically close the circuit of thesaid source through the heat-producing means to soften theheat-susceptible material, restore the openable joint to normal closedposition, break the circuit through the heat-producing means uponsuflicient heating, and hold the said joint closed until theheat-susceptible material cools and secures it in such position.

As inventor of the foregoing I hereunto subscribe my name in thepresence of two subscribing witnesses, this 25th day of July,

FRANK B. COOK. Witnesses:

FREDERICK R. PARKER, F. \V. PARDEE.

